One of England’s most famous landmarks, Stonehenge, has beaten a serious infestation of chafer grubs, thanks to a biological control from Scotts called Nemasys G, which uses nematodes to kill off pests naturally and safely. The ancient site, in Wiltshire, attracts 800,000 visitors a year, but when a long-standing chafer grub problem worsened last year and the pests began plaguing the grass pathways, English Heritage knew they had to find a solution quickly.

Chafer grubs are larvae of the garden chafer (Phyllopertha horticola), the most abundant chafer species in the UK. They grow to around 18mm in length and cause extensive damage to turf as they feed on grass roots. This problem was exacerbated at the site by jackdaws pulling up the grass to seek out the grubs, resulting in unsightly bald patches. English Heritage had to keep moving visitor paths away from the damage that encircled the famous stones, and there was another problem – when the chafer grubs hatched, the resulting swarm of beetles would fly up at the visitors who found it extremely off-putting to say the least.

Due to the large number of visitors, including children, and with local wildlife and sheep grazing in the neighbouring fields, English Heritage didn’t want to resort to using chemicals. So they needed a natural environmentally-friendly solution. In September 2006 Nemasys G was applied to 5,000m2 of grass to the south-east of the stones, and within a week of the first application the secondary damage from wildlife reduced considerably.

In April 2007, a review of the Nemasys G treatment at Stonehenge was carried out, which has led English Heritage to order more of the product – enough to treat an area twice the size of the original application.

Chris Bally, English Heritage’s landscape manager for Stonehenge and the south-west, commented: “Nemasys G has cured the treated areas. We found it extremely effective and chafer grubs have not caused us a problem at all this year on the treated areas. Now we are targeting other infected areas and hopefully we will not have a chafer grub problem at all in a couple of years.”